This time I will bring you the concept and usage analysis of JS command mode. What are the precautions when using the JS command mode concept and usage analysis. The following is a practical case, let's take a look.
This article mainly introduces the concept and usage of command mode in JS Design Pattern, briefly describes the principle and function of command mode, and analyzes the relevant definition and use of command mode in the form of javascript examples. For tips, friends who need them can refer to
The examples in this article describe the concept and usage of the command pattern of JS design pattern. Share it with everyone for your reference, the details are as follows:
The customer creates the command; the caller executes the command; the receiver performs the corresponding operation when the command is executed
Simple command objects are generally used to eliminate two objects (call (sender and receiver), while complex command objects are generally used to encapsulate indivisible or transactional instructions.
The main purpose of the command pattern is to isolate the calling object (user interface, API, proxy, etc.) from the object that implements the operation. This pattern can be used whenever the interaction between two objects requires a higher degree of modularity.
Command means using a simple method or function to perform the actual operation related to this command. Just like turning on the TV with a remote control, you can turn on the TV with just one button, which is simple and convenient. We don't need to care about its specific implementation operations. That's handled by the TV. The TV provides an interface (signal) to the remote control, and the remote control only needs to implement this interface when clicked.
Command: Define the interface of the command and declare the execution method.
ConcreteCommand: The command interface implementation object is a "virtual" implementation; it usually holds the receiver and calls the receiver's function to complete the operation to be performed by the command.
Receiver: Receiver, the object that actually executes the command. Any class may become a receiver as long as it can implement the corresponding functions required by the command.
Invoker: Requires the command object to execute the request. It usually holds the command object and can hold many command objects. This is where the client actually triggers the command and requires the command to perform the corresponding operation, which is equivalent to the entrance to the command object.
Client:Create a specific command object and set the receiver of the command object. Note that this is not a client in our conventional sense, but is assembling the command object and receiver. Perhaps it would be better to call this Client an assembler, because the client that actually uses the command triggers execution from the Invoker
Pattern Analysis
1. The essence of the command pattern is to encapsulate the command and separate the responsibility for issuing the command and the responsibility for executing the command.
2. Each command is an operation: the requesting party sends a request to perform an operation; the receiving party receives the request and performs the operation.
3. The command mode allows the requesting party and the receiving party to be independent, so that the requesting party does not need to know the interface of the party receiving the request, let alone how the request is received, and whether and when the operation is executed. Execution, and how it is executed.
4. The command mode makes the request itself an object, which can be stored and transferred like other objects.
5. The key to the command mode is the introduction of an abstract command interface, and the sender programs for the abstract command interface. Only specific commands that implement the abstract command interface can be associated with the receiver.
Advantages of the pattern
1. Reduce the coupling between objects.
2. New commands can be easily added to the system.
3. It is easier to design a combined command.
4. Call the same method to implement different functions
// 命令 var CreateCommand = function( receiver ){ this.receiver = receiver; } CreateCommand.prototype.execute = function() { this.receiver.action(); } // 接收者 电视 var TVOn = function() {} TVOn.prototype.action = function() { alert("TVOn"); } // 接收者 电视 var TVOff = function() {} TVOff.prototype.action = function() { alert("TVOff"); } // 调用者 遥控器 var Invoker = function( tvOnCommand, tvOffCommand ) { this.tvOnCommand = tvOnCommand; this.tvOffCommand = tvOffCommand; } Invoker.prototype.tvOn = function() { this.tvOnCommand.execute(); } Invoker.prototype.tvOff = function() { this.tvOffCommand.execute(); }
Execute Client
var tvOnCommand = new CreateCommand( new TVOn() ); var tvOffCommand = new CreateCommand( new TVOff() ); var invoker = new Invoker( tvOnCommand, tvOffCommand ); invoker.tvOn(); invoker.tvOff();
I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website !
Recommended reading:
JS imitation of Toutiao mobile homepage interface
eslint configuration during React development
Dynamic display of select drop-down list data
The above is the detailed content of JS command pattern concept and usage analysis. For more information, please follow other related articles on the PHP Chinese website!

Both Python and JavaScript's choices in development environments are important. 1) Python's development environment includes PyCharm, JupyterNotebook and Anaconda, which are suitable for data science and rapid prototyping. 2) The development environment of JavaScript includes Node.js, VSCode and Webpack, which are suitable for front-end and back-end development. Choosing the right tools according to project needs can improve development efficiency and project success rate.

Yes, the engine core of JavaScript is written in C. 1) The C language provides efficient performance and underlying control, which is suitable for the development of JavaScript engine. 2) Taking the V8 engine as an example, its core is written in C, combining the efficiency and object-oriented characteristics of C. 3) The working principle of the JavaScript engine includes parsing, compiling and execution, and the C language plays a key role in these processes.

JavaScript is at the heart of modern websites because it enhances the interactivity and dynamicity of web pages. 1) It allows to change content without refreshing the page, 2) manipulate web pages through DOMAPI, 3) support complex interactive effects such as animation and drag-and-drop, 4) optimize performance and best practices to improve user experience.

C and JavaScript achieve interoperability through WebAssembly. 1) C code is compiled into WebAssembly module and introduced into JavaScript environment to enhance computing power. 2) In game development, C handles physics engines and graphics rendering, and JavaScript is responsible for game logic and user interface.

JavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.

Python is more suitable for data science and automation, while JavaScript is more suitable for front-end and full-stack development. 1. Python performs well in data science and machine learning, using libraries such as NumPy and Pandas for data processing and modeling. 2. Python is concise and efficient in automation and scripting. 3. JavaScript is indispensable in front-end development and is used to build dynamic web pages and single-page applications. 4. JavaScript plays a role in back-end development through Node.js and supports full-stack development.

C and C play a vital role in the JavaScript engine, mainly used to implement interpreters and JIT compilers. 1) C is used to parse JavaScript source code and generate an abstract syntax tree. 2) C is responsible for generating and executing bytecode. 3) C implements the JIT compiler, optimizes and compiles hot-spot code at runtime, and significantly improves the execution efficiency of JavaScript.

JavaScript's application in the real world includes front-end and back-end development. 1) Display front-end applications by building a TODO list application, involving DOM operations and event processing. 2) Build RESTfulAPI through Node.js and Express to demonstrate back-end applications.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

Atom editor mac version download
The most popular open source editor

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

SublimeText3 English version
Recommended: Win version, supports code prompts!

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.
